Plastics are inexpensive and durable materials, which are employed to manufacture a variety of products that find uses in a wide range of applications. As a consequence, the production of plastics has increased dramatically over the last decades. A large part of these plastics are used for single-use disposable applications, or for short-lived products (such as bags, packaging including trays, containers, bottles, agricultural films, etc.) that are discarded within a year of manufacture. Because of the durability of the polymers involved and their high resistance to biodegradation (due to high molecular mass values, hydrophobicity and crystallinity), substantial quantities of plastics are piling up in landfill sites and in natural habitats, generating increasing environmental problems worldwide.
To answer these problems, different physical, chemical and/or biochemical approaches have been developed to reduce the biodegradation resistance of polymers and to increase their biodegradation rate. For example, biodegradable plastic products have been developed. However, the environmental degradation conditions are not optimal for such biodegradable plastics and their degradation generally takes place partially.
Recently, a novel plastic material has been developed that contains a small amount of biological entities having a polymer-degrading activity. The biological entities are interestingly able to degrade at least one polymer of said plastic material. The process for manufacturing such plastic material has been described in patent application WO 2013/093355. The plastic material obtained by this process contains biological entities dispersed in a polymer, and is directly usable through an extrusion die for producing plastic articles having improved biodegradability.
The present invention provides improved methods and compositions for producing plastic articles with increased biodegradability. The inventors have developed masterbatch compositions containing high concentrations of biological entities dispersed in a carrier material and they have shown that such compositions may be used to produce plastic materials with remarkable properties. In particular, the compositions and methods of the invention allow the production of plastic articles with an improved dispersion and distribution rate of biological entities in the plastic article, thus leading to an improved control of the biodegradability. Furthermore, the methods of the invention can be used in standard operations of plastics processing and do not impair the mechanical properties of the resulting plastic articles.